LIGHT SURGE AT HIGHWAY SPEEDS. GMC Truck Jimmy

REVISION: 09/05/97

THIS BULLETIN IS BEING REVISED TO CHANGE EMISSION AXLE UNDER S/T UTILITY. PLEASE DISCARD CORPORATE BULLETIN 57-65-03 (SECTION 6E-- ENGINE FUEL & EMISSION). ______________________________________________________________________

SUBJECT: LIGHT SURGE AT HIGHWAY SPEEDS AT LIGHT THROTTLE (NEW CALIBRATIONS)

MODELS: 1994 CHEVROLET AND GMC TRUCK S/T MODELS 1994 OLDSMOBILE BRAVADA WITH 4.3L V6 ENGINE (VIN W - RPO L35) AND AUTOMATIC TRANSMISSION

CONDITION:

SOME OWNERS MAY COMMENT ON A LIGHT HIGHWAY SURGE CONDITION (MINOR ENGINE RPM INSTABILITY). THIS CONDITION MAY OCCUR AT HIGHWAY SPEEDS WITH LIGHT THROTTLE.

CAUSE:

CALIBRATION PARAMETERS NOT OPTIMIZED FOR THIS OPERATING CONDITION.

CORRECTION:

IF STANDARD DIAGNOSTIC PROCEDURES FOR THE ABOVE CONDITIONS DO NOT RESOLVE THE PROBLEM, THE FOLLOWING CALIBRATIONS (FOR THIS SPECIFIC LISTED CONCERN) MAY RESOLVE THE PROBLEM.

SERIES EMISSION OLD CALIBRATION NEW CALIBRATION TRUCK AXLE (RATIO) P/N B/C P/N B/C ______ ____________ _______________ _______________

S/T NATIONWIDE 16195891 BHRH 16219023 BPLC PICKUP GU4 (3.08) GU6 (3.42) GT4 (3.73)

S/T NATIONWIDE 16195894 BHRJ 16219020 BPLB UTILITY EXCLUDING CTF ENGINE GU4 (3.08) GU6 (3.42) GT4 (3.73)

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE: LABOR CODE: J6364 LABOR TIME: USE PUBLISHED LABOR TIME.

FIGURES: 0 ATTACHMENTS: 0

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.